Magnetic gun



Sept. 10, 1940. w E, FERRY 2,214,297y

MAGNETIC GUN Filed Dec. 13, 1938 2 Shoets-Sheet l PMECTORS Sept. l0, 1940. w,`E FERRY 2,214,297

MAGNETIC GUN Filed Das. 13, 193s 2 sums-snm 2 g in? Syvum/vtm 'SEARQH R@ ANU limo/2i.. como PEGJECTURS,

Patented Sept. '10, v1940 UNITED STATES sit/with PATENT OFFICE 20 Claims.

This invention relates to electromagnetic guns and its primary object is to provide an electromagnetic gun for propelling a stream of magnetic particles at high velocity for shaping or cutting metal, stone or like materials by impact.

In general it is an object of my invention to provide a magnetic conveyor for rolling magnetic objects in which the propelling magnetic flux lines are substantially parallel with the axes about which the objects turn as they roll along the conveyor.

Another object is tol provide an electromagnetic gun which shoots a plurality of streams of small pellets at a high velocity. Still another object is to provide an electromagnetic gun with means by which the effective bore may be adjusted in size to handle pellets of different diameter. A specific object of the invention is to provide a feed control for feeding pellets into the bore of an alternating current excited gun at a rate in substantial synchronism with the frequency of the current. It is also an object of my invention to provide an electromagnetic gun in which pellets roll along the sides of the bore instead of on the bottom.

In the drawings:

Figure 1 is a side view of an electromagnetic gun partly in section showing how my invention may be carried out.

Figure 2 is a plan view of a portion of the gun shown in Figure 1.

Figure 3 is a transverse sectional view taken on line 3--3 of Figure 2.

Figure 4 is an enlarged transverse sectional view taken on line 4 4 of Figure 1, the winding being omitted for clarity.

Figure 4a is a view similar to Figure 4 but showing a modication. f

Figure 5 is a longitudinal side View partly diagrammatic showing the preferred winding scheme employed.

Figure 6 is a partly section side view showing the feed mechanism.

Figures 7 and 8 are end and side views respectively of the barrel of a still further modification of my invention.

Figure 9 is an end view of another modification.

Figure 10 is an end view of a simplified form of the invention.

In Figure 1 the gun is shown as consisting of a barrel portion I0, a stock I I, a supply hopper I2 and handles I5 and I6, the handle I6 also including a. trigger switch I1 which controls the flow of current from the feed line I8 tothe windings on the stator.

The barrel of the gun preferably consists of upper and lower stator members and 2|, respectively, each member having at the center a laminated portion 23 and 24, and between the two portions there may be clamped one or more races 26 made of tough non-magnetic material, capable of withstanding the rough usage to which they will be subjected. Between .the two races is a non-magnetic spacer 28 of diamond shape in cross section so as to make the non-magnetic portion of the flux path longer in the center 28 than at the sides 28 thus forcing the flux to traverse the channel as shown by the arrows 29 and creating a concentrated field at the side of the channel rather than along the middle. Considering a cross-section of the barrel it will be seen that the lines of ux cut what is substantially a segment of the section and that the eld is stronger near the apex of the arc of the segment than at the chord. Another reason for having the spacer 28 diamond shape is to facilitate the assembly of the gun barrel. The crosssectional shape of each race is preferably elliptical having its vertical minor diameter slightly greater than the diameter of the pellets 30 which move through the races, and as shown in Figure 7 having its major diameter greater than twice the diameter of the pellets whereby two streams of pellets may flow through the bore without touching. Although the diameters given are preferred I find that there is no interference if the major' diameter is considerably less than twice the diameter of the pellets as shown in Figures 4, 4a and in Figure 9. The reason there is no interference is that the contacting surfaces of the pellets on opposite sides of the bore aremoving in the same direction. If the pellets on one side of the bore should follow too closely and come into contact the gear action due to the contacting surfaces moving in opposite directions would throw the interfering pellet out of the channel and into the opposite channel.

'Ihe modification in Figure 4a shows three bores having liners 26', 26', and 32, the center bore and liner 32 having a major diameter substantially twice its minor diameter to accommodate two streams of pellets and also having two spaced pairs of laminated stator cores 33 instead of a single pair as in the double barrelled modification shown in Figure 4. Again it may be pointed out that the gun may use pellets having diameters larger than those illustrated, the only requirement being that the diameter not be so great that the pellets cannot roll on the sides of the bore.

The particular arrangement of the stator cores with respect to the bores or ball races causes the balls or pellets to travel on the side walls of the races rather than on the bottom, with the result that the frictional resistance is greatly reduced since the magnetic eld being concentrated along the sides helps to support the balls or pellets. It will be noted that the laminated core extends only to about the vertical diameters of the ball races which results in a concentrated eld of flux at the sides that forces the pellets to the side Walls as already mentioned, thelines of magnetic ux being indicated by the arrows 29. The presence of the pellets in the races tends furtherfto con--y centrate the ux at the sides Afor the reason that the air gap between the pellets and the core increases from the point of contact toward the vertical diameter. It is well known that a free magnetic body in a magnetic field will position itself to accommodate the greatest number of lines of flux.

The windings are preferably distributed along the stators forming the barrel in a manner to generate a travelling field of approximately constant force (Figure 5).V In order to accomplish this I find it best to 'divide the length of the stators into a number of equal parts by a series of equally spaced slots approximately as follows, assuming a three-phase winding. In' the first pair of opposing slots a, a I place the turn or turns of phase A. In the next three pairs of opposing slots b--b I place the turns of phase B. In the next ve pairs of opposing slots c'-c I place the turns of phase C. The next seven pairs of slots a1, a1, will contain the turns of `phase A for the second pole and the turns of phase B will be distributed in the next nine slots b9, b9 and finally the turns of phase C will be distributed in the next eleven slots cl I, cl I.` In order that a constant accelerating force be imposed on the pellets each slot should have a sufficient number of turns to produce as far as possible the same number of ampere turns per slot. Near the muzzle the turns may be arranged to produce a concentrated field m and a neutral field n just back of the concentrated end zone may be provided in order that the pellets may continue their travel and not be subjected to a retarding' pull as they leavethe muzzle. This zone may be produced by bridging a' portion of the cores with magnetic material. The windings may be mounted separately on the upper and lower stators respectively as in Figure 7 or they may be` helically wound with the opposite sides of the turns in the opposing slots of each pair as indicated in'Figure 5. The art of winding stators is well understood and further description is unnecessary, the only requirement being that the ampere turns be distributed so as to produce a substantially uniform accelerating force. The windings may be formed inthe slots or preformed and placed in the slots according to almost any of the numerous systems now employed for producing travelling elds in electric machines.

As shown in Figures 1 and '7 the two stators forming the barrel of the gun are releasably held' together as by bolts 40 in order thatthe upper and lower portions of the stators may be separated slightly to permit the withdrawal or insertion of the barrel liners 26. The reason it is Y preferred to have these liners removable'is, rst,

that they become Worn and must be replaced and second that thick liners may be replaced by thin liners thereby to eiect a change of the bore diameter to accommodate diierent sized pellets.

The synchronous valve mechanism shown in Figure 6 consists of a tubular plunger 42 mounted to reciprocate in the breech end coaxially of the bore 44 and having in its upper side one or more apertures 45 by which pellets from the container or hopper I2 may pass into the bore of the gun from the apertures 46 in the bottomoi the hopper. Spring means 48 surrounding the plunger and bearing against its rim 49 at one end and seated against the stop 50 just ahead of the apertures 46 tends to keep the plunger in a valve closing position as shown in dotted lines at 52. In this closed position the apertures 45 are out of registration with the apertures 46 in the bottom of the hopper. Within the tubular plunger 42 is a solid plunger 54 connected to a vibrating arm 56 by means of adjusting nuts 58. The arm is made to vibrate by the electromagnet 66 which is energized by a coil 6l connected to phase B or phase C of the gun winding so that the arm 56 vibrates in synchronism with the moving eld flux; the reason'for energizing the coil 6l with current from either'phase vB or phase C is to avoid time lag of the pellets with respect to phase A which lag would be present if coil 6I were excited by current from phase A. Where two valve mechanisms are used for starting the pellets through a double channel bore it is preferred that the coils on the two valves be energized from different phases so that there will be a definite lag of alternate pellets. The arm 56 may be magnetic or it may carry an armature 63 for attraction by the electromagnet 68. The arc of motion of the arm 56 is adjusted by means of a set screw 65 having lock nuts 66. The length of the plunger 54 may be adjusted by means of the locknuts 58.

During operation the vibration of the arm 56 with the plunger 54 tends to keep the plunger 42 in the position shown in full lines, thereby permitting ypellets to gravitate into the bore of the tube where they are struck by the solid plunger 54 and thereby given an initial impulse into the travelling field. 'Ihis construction prevents the pellets from jamming and also provides a positive start which brings the pellets into substantial synchronism with the traveling iield. Only one valve is shown in Figure 6 but it is to be understood that as many valves are to be provided as there are bores for the gun.

Figures 7 and 8, which are viewsof the end portion of an air-cooled or ventilateddouble barreled modification of the invention, show central laminated cores 10, 1I- held between the vertically arranged non-magnetic spacer plates 13,v 14 which platesV separate the central cores from the outside cores 15, 16 and 11, 18 respectively. The upper horizontal bolts 19 hold the upper cores 10, 15 and 11 and upper spacers 13, 13 rigidly together to form the upper part 80 of the barrel I 0 which upper part is in turn held by the vertical bolts 40 on the lower part 8| formed by the lower cores 1I, 16 and 18 and lower spacer plates 14, 14 all clamped rigidly together by the horizontal bolts 82.

The adjacent corners of the cores are each provided with quarterround grooves which cooperate with the inner ends of the spacer plates 13,- 14 to form bores of elliptical cross section which bores contain non-magnetic liners 83, 84 that are each open at one side 85, 86. If desired adjacent ends 88 of the outside laminationsofyth'e cores 15--18 may be turned horizontally inward to form a track for the balls or pellets 3|) and also to form a ledge to receive the spaced edges 89 of the open sided liners 83 and 84, however this increases the cost of the apparatus and its advantages may not warrant the extra expense. The passage of the balls through the bores moves a considerable quantity of air through the long side openings and 86 and thus carries away a great deal of heat generated in the cores when the glm is in operation. The windows 85 and 86 also permit easy location and release of any jams that may occur. Side braces 92 may be employed to hold the upper and lower parts in rigid relation. The liners 83 and 8,4 in the modification shown in Figures 7 and 8 may be removed by loosening the horizontal bolts 19, 82 and the side braces and also the vertical bolts 40 if necessary.

In Figure 9 the two stators 95, 96 forming the barrel are adjustably held in spaced relation by bolts 91 and 98 carried by the L-shaped lugs 99 and |09 secured to the two stators. The windings are indicated at |ll|. This mod'ication provides for ample cooling as the air may flow freely through both side openings |03 and |05 and it also provides simple means for adjusting the size of the bore, as by turning the bolts 91 and 98.

In Figure 10 is illustrated a simple conveyor for rolling objects |20 in which the laminated cores |2| are horizontal and the windings |22 are arranged to produce a travelling ux |23 AVthat traverses the channel |24 horizontally as it moves along the channel. A rolling object such as a ball |20 in the conveyor will turn about an axis |25 which is parallel or substantially parallel with the field flux |23.

In operation it will be seen that each ball rotates about an axis which is roughly parallel with the lines of flux 29 which means that each ball rotates about an axis through or near its north and south magnetic poles. are not fixed but remain sufficiently constant with respect to the axis of rotation as to reduce materially the hysteresis loss that would occur should the balls rotate about axes normal toy the lines of magnetic flux, a condition that exists when the flux lines traverse the bore uniformly causing the balls to roll on the bottom of the bore. Rolling on the bottom produces a continuously changing polarity unless the lines of flux are horizontal (as in Figure 10) in which case the balls would roll about their polar axes but the rolling friction would be a maximum.

However, the speed of `the balls through the bore is so great as probably to render both the friction and hysteresis losses negligible and as far as now can be determined the primary benefit of having the balls roll on opposite walls is the prevention of jams.

What I claim is:

1. In an electromagnetic gun, a barrel and means along the barrel for producing a travelling magnetic field in which the flux that transverses the bore is concentrated along one side.

2. In an electromagnetic gun, a barrel, means along the barrel for producing a travelling magnetic field in which the bore transversing flux is concentrated along one side of the barrel and means for feeding spherical pellets into the barrel whereby the pellets roll along said one side about axes through their north and south magnetic poles.

3. In an electromagnetic gun, a barrel member Of course these poles DLAHLH HUU divided longitudinally and having between its two parts a pair of spaced air gaps comprising the bores of the gun, a magnetic core irr each part having transverse slots, polyphase windings in said slots for forming a travelling eld in said air gaps, said cores being positioned to concentrate the flux along the sides of the bores and releasable means clamping said parts together.

4. A magnetic gun comprising a barrel member divided longitudinally and having between its two parts an elongated air gap forming the bore of the gun, said bore being open on one side, and a longitudinally split tubular liner in said bore, a magnetic core on each part, means for holding the sides of the liner apart forming an opening in registration with said open side and releasable means clamping the two parts together whereby permitting removal and replacement of the liner.

5. In an electromagnetic gun, a barrel having a bore therethrough and means along the length of the bore for producing a travelling eld moving through the bore toward the muzzle, the lines of ux of said iield being chords with respect to cross-sections of the bore and being` most concentrated along one side of the bore whereby pellets travel along said side.

6. In an electromagnetic gun, a barrel member having a bore therethrough and means along the length of the barrel member for producing a magnetic field travelling through the bore toward the muzzle of the gun, said means being arrangedto cause the flux of said field to cut a segment of about a hundred and eighty degrees of said bore and being more concentrated near the apex of the segment than at the chord'.

7. In an electromagnetic gun, a barrel member divided longitudinally and having between its two parts a pair 4of laterally spaced air gaps forming two bores for the gun, a magnetic core in each part, said cores extending toward each other a substantial distance between the bores, the opposing faces of the co-res being spaced apart `and each side of each core having a substantially quarter round groove forming about ninety degrees of each bore, whereby the adjacent hundred and eighty degrees of the bores are faced with magnetic material and non-magnetic material forming the rest ofV the barrel whereby when the cores are excited the resulting magnetic flux cuts only one side of each bore.

8. In an electromagnetic gun, a barrel polyphase coil, means along the barrel for producing an alternating travelling magnetic eld and electromagnetic means for feeding pellets into the barrel in synchronism with the magnetic field, said electromagnetic means including an energizing coil connected to a single phase of said field producing means so as to operate in phase with but rone of the phases thereof.

9. An alternating current magnetic gun for projecting a stream of magnetic pellets, polyphase coils alternately distributed along the barrel of the gun, means for supplying pellets to the gun and a valve synchronized with the alternating eld of the gun for controlling the flow of pellets from the supply into the bore of the gun, electromagnetic means for operating said valve including an energizing coil connected so that the pellets enter the gun barrel slightly in lead oi.' the eld.

10. A magnetic gun comprising a barrel having a breech and muzzle connected by a channel, means providing a travelling magnetic field along said channel, and electromagnetically vibrated spring means at the breech for feeding pellets successively into said channel. l

11. The device of claim 10 in which the feeding means is operated by alternating current.

12. A magnetic gun comprising a barrel having a breech and a muzzle connected by a channel, means at the breech for holding a supply of magnetic pellets, means for permitting pellets to gravitate into the channel from the supply at a desired rate, means providing a progressive alternating magnetic field moving along said channel toward the muzzle and impact means at the breech for giving the pellets a starting impulse whereby they step into synchronism with the travelling field. j

13. In a magnetic gun, a barrel member having a breech and muzzle connected by a channel, means for producing a travelling` alternating magnetic field along a channel jtoward the muzzle, means at the breech for holding a supply of magnetic pellets, means providing a passageway by which the pellets may gravitate into the channel, means including a plunger in the breech for controlling the passage of pellets into the channel and alternating current means for causing the plunger to vibrate at substantially the rate of alternation of the eld.

14. In an electromagnetic gun, a `barrel member comprising an upper and lower part having between them an air gap forming the bore of the gun, a side of said bore being open the greater portion of its length, the width of, the opening being less than the diameter of the` bore, means along the barrel member for producing a travelling magnetic eld in the bore and moving toward the muzzle, said upper and lower parts including magnetic cores positionedto concentrate the flux of said field along said open side whereby magnetic pellets moving through the barrel roll along said open side. l

15. An electromagnetic gun comprising a barrel member having two laterally spaced channels, said channels being substantially l elliptical in cross section, the adjacent sides of said channels being closed and the far sides being open, removable liners in said channels and means for producing a travelling magnetic field moving along said channels toward the muzzle, magnetic cores in said barrel member positioned to cause the flux of the eld to be concentrated more at the sides than at the middle of the channels whereby magnetic pellets roll along the sides of the channels instead of on the bottom.

16. In a magnetic gun for shooting a stream of pellets, a barrel having a breech and muzzle connected by a bore, means providing a magnetic field along said bore for propelling pellets therethrough, a supply hopper on the barrel having an aperture adjacent the breech, a gate member mounted to reciprocate between the aperture and the breech and having an opening therein adapted to register with said aperture when the member` is in firing position, spring means normally keeping the gate member out of said position and vibrating means operable when the gun is in use for moving the gate member into ring position.

17. The device of claim 16 in which said vibrating means includes a plunger mounted to vibrate coaxially of the bore and adjacent said opening whereby as the pellets come through the opening they are struck by the plunger and propelled into said bore.

18. In an electromagnetic gun, a pair of longitudinal barrel members spaced to form between them the bore of the gun, a hopper mounted on the barrel members and having an aperture adjacent the breech, a tubular plunger mounted to reciprocate coaxially of the bore and having an opening adapted to register with said aperture when the plunger is in firing position whereby ammunititon may pass from the hopper into the tubular plunger and means vibrating in said plunger for striking the ammunition and propelling it into the gun bore.

19. In an electromagnetic gun, a barrel comprising two longitudinal members cooperatively grooved to form the bore of the gun, and means for holding said members in cooperative rela-V tion to form said bore, said means being adjustable to vary the distance between said members whereby the diameter of said bore may be changed to accommodate diil'erent size ammunition.

20. An electromagnetic device for propelling rolling magnetic objects comprising a track, means along the track for producing a travelling magnetic field and means for causing the flux lines of the field to traverse objects rolling on the track in a direction substantially parallel with the axes of rotation of the objects.

' WILLIAM E. FERRY. 

